The above link takes you through a couple of questions to see if you can exchange your licence. According to the GOV.UK link above you must be a resident and to be a resident you must have lived in the UK for 185 days. The 1st question:
1 Are you a resident of Great Britain?
You're normally a resident if you have a permanent address in Great Britain that you’ve lived at for at least 185 days.
Despite what it says, there have been many people here on the forum who have applied for and received a provisional licence before they have been in the UK for 6 months.
It's not been a problem.
The wording seems slightly different now, but the website used to say that a resident was defined as someone who had
permission to live in the UK for more than 185 days, not that they actually had to have already been here for 185 days. So the fact that you had a fiance or spousal visa on the settlement path was enough to show that you were a resident.
I believe the 6 month residence stipulation is mainly aimed at EEA citizens who have to be properly resident in the UK to be able to exchange a licence here... they are trying to stop them from coming to the UK, getting a UK licence and then going back to their home country.
From the booklet about new residents and driving in the UK (
http://www.direct.gov.uk/prod_consum_dg/groups/dg_digitalassets/@dg/@en/@motor/documents/digitalasset/dg_068659.pdf):
Taking a test
To take a GB driving test, you normally have to live in Great Britain. If you have recently moved to Great Britain from another EU/EEA country, you must have lived in Great Britain for at least 185 days in the 12 months before taking the test and applying for a full driving licence.
and
Rules for exchanging your licence
You must normally live in Great Britain and have a permanent address here.
If you:
– have an EU/EEA licence
– apply for a GB driving test at the same time as exchanging your licence, and
– have moved to Great Britain after recently living in another EU/EEA country, you must have lived in Great Britain for at least 185 days in the 12 months before you apply for a full driving licence.
and
How to apply for a provisional GB driving licence
If you need to pass a GB driving test to get a full GB licence, you must first apply for a provisional driving licence. To do this you should fill in ‘Application for a driving licence’ (D1) and send it to us at DVLA, Swansea, SA99 1AF with the correct fee (see section 9 of this booklet for details of how to get our forms and leaflets).
Notice there is no mention of having to live in the UK for 185 days if you want to apply for a provisional licence.
It only mentions 185 days in relation to exchanging your licence if you have moved from another EU/EEA country. People from the US with US licences cannot exchange them, so this doesn't apply to them anyway.